Manufacturing method of tft substrate and tft substrate

ABSTRACT

A TFT substrate and a manufacturing method thereof are provided. In the manufacturing method, a metal oxide semiconductor layer is irradiated with UV light by using a gate as a shielding layer, such that a portion of the metal oxide semiconductor layer irradiated by the UV light is conductorized to form a source, a drain, and a pixel electrode, and a portion of the metal oxide semiconductor layer shielded by the gate still retains semiconductor properties to form a semiconductor channel. The invention achieves the alignment of the source and the drain with the gate by processes of self-alignment of the gate and conductorization of the metal oxide semiconductor layer, and can effectively control an overlapping region of the source and drain and the gate. Thereby, the parasitic capacitance is reduced, and the display quality is improved. Also, the manufacturing method is simple, and the production efficiency is improved.

FIELD OF INVENTION

The present invention relates to display technology, and moreparticularly to a manufacturing method of a TFT substrate and a TFTsubstrate.

BACKGROUND OF INVENTION

In the field of display technology, flat panel displays, such as liquidcrystal displays (LCDs) and active matrix organic light-emitting diode(AMOLED) displays, have gradually taken place of cathode ray tubedisplays, and are widely used in LCD TVs, mobile phones, personaldigital assistants, digital cameras, computer screens, or laptopscreens.

A display panel is an important part of the LCD and OLED displays.Whether LCD display panel or OLED display panel, there is usually a thinfilm transistor (TFT) substrate. Taking the LCD display panel as anexample, it is mainly composed of a TFT substrate, a color filter (CF)substrate, and a liquid crystal layer disposed between two substrates,and its working principle is to control rotation of liquid crystalmolecules in the liquid crystal layer by applying a driving voltage onthe TFT substrate and the CF substrate, and the light of a backlightmodule is refracted to generate a picture. Therefore, the thin filmtransistors are the main driving components in current LCD and OLEDdisplays, and are directly related to the development direction of highperformance flat panel display devices.

The thin film transistors have a plurality of structures, and there aremany kinds of material for fabricating active layers of the thin filmtransistors with corresponding structure, wherein metal oxide thin filmtransistors (metal oxide TFTs) have advantages of high field effectmobility (10 cm²/V·s), simple fabrication process, good uniformity inlarge area deposition, fast response speed, and high transmittance inthe visible light level. It is considered to be the most promisingbackplane technology of the development of the display in the directiontowards large size and flexibility.

With the increasing resolution of the LCD and OLED displays, theproportion of the thin film transistors per unit area is alsoincreasing. Referring to FIG. 1, in the existing TFT substrate, thereare partial overlapping regions between a gate 110 and a source 120, andbetween the gate 110 and a drain 130 in a direction perpendicular to asubstrate 100, resulting in a gate-drain parasitic capacitance Cgd and agate-source parasitic capacitance Cgs of the thin film transistor, and aratio relative to the storage capacitance also increases. Therefore,when the aforementioned thin film transistors are applied to a drivingcircuit of the display panel, a considerable resistance-capacitanceloading (RC loading) is often be generated in the signal transmission,resulting in decline in the display quality of the display.

SUMMARY OF INVENTION

The object of the present invention is to provide a manufacturing methodof a TFT substrate, which achieves the alignment of a source and drainwith a gate by processes of self-alignment of the gate andconductorization of a metal oxide semiconductor layer, and anoverlapping region of the source and drain and the gate can beeffectively controlled. Thereby, the parasitic capacitance is reduced,and the display quality is improved.

The object of the present invention is also to provide a TFT substrate,which is fabricated by the manufacturing method of the TFT substrate ofthe present invention. The TFT substrate can effectively control theoverlapping region of the source and drain and the gate. Thereby, theparasitic capacitance is reduced, and the display quality is improved.

To achieve the aforementioned object, the present invention provides amanufacturing method of a TFT substrate including the following steps.

A step S1, a base substrate is provided. A metal oxide semiconductorlayer is deposited on the base substrate. The metal oxide semiconductorlayer is patterned to obtain a first preliminary pattern and a secondpreliminary pattern connected to a side of the first preliminarypattern.

A step S2, a first metal layer is deposited on the base substrate andthe metal oxide semiconductor layer. The first metal layer is patternedto obtain a connecting block connected to another side of the firstpreliminary pattern. The connecting block is heated. Thereby inducing aportion of the first preliminary pattern in contact with the connectingblock to be conductorized.

A step S3, a gate insulating layer is deposited on the base substrate,the metal oxide semiconductor layer, and the first metal layer. A secondmetal layer is deposited on the gate insulating layer. The second metallayer is patterned to obtain a gate across the first preliminarypattern.

A step S4, the first preliminary pattern and the second preliminarypattern are irradiated with UV light from above the base substrate byusing the gate as a shielding layer, such that a portion of the firstpreliminary pattern correspondingly located at two side of the gate andrespectively connected to the connecting block and the secondpreliminary pattern is conductorized under UV light irradiation to forma source and a drain spaced apart, the second preliminary pattern isconductorized under the UV light irradiation to form a pixel electrode,and a portion of the first preliminary pattern located between thesource and the drain and shielded by the gate forms a semiconductorchannel.

The step S1 further includes forming an organic photoresist bump on thebase substrate before depositing the metal oxide semiconductor. Thefirst preliminary pattern correspondingly covers the organic photoresistbump on the base substrate.

The material of the organic photoresist bump is a light-shieldingmaterial.

A height of the organic photoresist bump is greater than 2 μm.

A portion of the first metal layer in contact with the metal oxidesemiconductor layer is a metal inducing layer, and a material of themetal inducing layer is aluminum.

The first metal layer after patterning in the step S2 further includes adata line connected to the connecting block.

The second metal layer after patterning in the step S3 further includesa gate line vertically insulated and crossed with the data line andconnected to the gate.

The invention further provides a TFT substrate including a basesubstrate and a metal oxide semiconductor layer, a first metal layer, agate insulating layer, and a second metal layer sequentially depositedon the base substrate from bottom to top.

The metal oxide semiconductor layer includes a semiconductor channel anda source, a drain, and a pixel electrode which are conductorized.

The first metal layer includes a connecting block connected to thesource.

The second metal layer includes a gate correspondingly covering thesemiconductor channel.

The pixel electrode is connected to the drain. The source and the drainare respectively connected to the semiconductor channel from both sidesof the semiconductor channel and are spaced apart by the semiconductorchannel. Opposite inner side edges of the source and the drain arealigned with two side edges of the gate.

The TFT substrate further includes an organic photoresist bump disposedbetween the base substrate and the metal oxide semiconductor layer. Thesource, the semiconductor channel, and the drain connected togethercorrespondingly cover the organic photoresist bump.

A material of the organic photoresist bump is a light-shieldingmaterial.

A height of the organic photoresist bump is greater than 2 μm.

A portion of the first metal layer in contact with the metal oxidesemiconductor layer is a metal inducing layer, and a material of themetal inducing layer is aluminum.

The first metal layer further includes a data line connected to theconnecting block.

The second metal layer further includes a gate line vertically insulatedand crossed with the data line and connected to the gate.

The beneficial effects of the present invention are as follows. In themanufacturing method of the TFT substrate provided by the presentinvention, the metal oxide semiconductor layer is irradiated with UVlight by using the gate as the shielding layer, such that the portion ofthe metal oxide semiconductor layer irradiated by the UV light isconductorized to form the source, the drain, and the pixel electrode,and the portion of the metal oxide semiconductor layer shielded by thegate still retains semiconductor properties to form the semiconductorchannel. The invention achieves the alignment of the source and thedrain with the gate by processes of self-alignment of the gate andconductorization of the metal oxide semiconductor layer, and caneffectively control an overlapping region of the source and drain andthe gate. Thereby, the parasitic capacitance in the device is reduced,the RC loading when transmitting the signal is reduced, and the displayquality is improved. Also, the manufacturing method is simple, and theproduction efficiency is improved. The TFT substrate of the presentinvention is fabricated by the aforementioned manufacturing method ofthe TFT substrate, and can effectively control the overlapping region ofthe source and drain and the gate. Thereby, the parasitic capacitance inthe device is reduced, the RC loading when transmitting the signal isreduced, and the display quality is improved.

DESCRIPTION OF DRAWINGS

The technical solution, as well as other beneficial advantages, of thepresent invention will become apparent from the following detaileddescription of an embodiment of the present invention, with reference tothe attached drawings. In the drawings:

FIG. 1 is a schematic structural view of an existing TFT substrate.

FIG. 2 is a schematic flowchart of a manufacturing method of a TFTsubstrate of the present invention.

FIG. 3 is a schematic view showing a step S1 of the manufacturing methodof the TFT substrate of the present invention.

FIG. 4 is a schematic view showing a step S2 of the manufacturing methodof the TFT substrate of the present invention.

FIG. 5 is a schematic view showing a step S3 of the manufacturing methodof the TFT substrate of the present invention.

FIG. 6 is a schematic view showing a step S4 of the manufacturing methodof the TFT substrate of the present invention, and a schematicstructural view of a TFT substrate of the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

To further expound the technical solution adopted in the presentinvention and the advantages thereof, a detailed description is given toa preferred embodiment of the present invention with reference to theattached drawings.

Referring to FIG. 2, the present invention first provides amanufacturing method of a TFT substrate including the following steps.

A step S1, as shown in FIG. 3, a base substrate 10 is provided. Anorganic photoresist bump 20 is formed on the base substrate 10. A metaloxide semiconductor layer 30 is deposited on the base substrate 10 andthe organic photoresist bump 20. The metal oxide semiconductor layer 30is patterned to obtain a first preliminary pattern 31 correspondinglycovering the organic photoresist bump 20 and a second preliminarypattern 33 connected to a side of the first preliminary pattern 31.

Particularly, material of the organic photoresist bump 20 is alight-shielding material, and a height of the organic photoresist bump20 is greater than 2 μm.

Particularly, in the step S1, a material of the metal oxidesemiconductor layer 30 may be indium gallium zinc oxide (IGZO), indiumzinc tin oxide (IZTO), or indium gallium zinc tin oxide (IGZTO). In thepresent embodiment, the metal oxide semiconductor layer 30 is preferablyIGZO.

A step S2, as shown in FIG. 4, a first metal layer 40 is deposited onthe base substrate 10 and the metal oxide semiconductor layer 30. Thefirst metal layer 40 is patterned to obtain a data line 45 and aconnecting block 41 connected to the data line 45 and the firstpreliminary pattern 31 on both ends respectively. The connecting block41 and the second preliminary pattern 33 are respectively connected toopposite sides of the first preliminary pattern 31. Then, the connectingblock 41 is heated to induce the first preliminary pattern 31 in contactwith the connecting block 41 to be conductorized by the high temperatureconnecting block 41.

Particularly, a portion of the first metal layer 40 in contact with themetal oxide semiconductor layer 30 is a metal inducing layer which caninduce the metal oxide semiconductor layer 30 to be conductorized athigh temperature, and a material of the metal inducing layer is aluminum(AI), nickel (Ni), etc. In the present embodiment, the first metal layer40 is preferably a molybdenum aluminum stacked layer (Mo/AI), whereinthe aluminum layer is in contact with the metal oxide semiconductorlayer 30.

A step S3, as shown in FIG. 5, a gate insulating layer 50 is depositedon the base substrate 10, the metal oxide semiconductor layer 30, andthe first metal layer 40. A second metal layer 60 is deposited on thegate insulating layer 50. The second metal layer 60 is patterned toobtain a gate 61 across the first preliminary pattern 31 and a gate line65 vertically insulated and crossed with the data line 45 and connectedto the gate 61.

Particularly, the gate insulating layer 50 is a silicon oxide layer, asilicon nitride layer, or a combination thereof.

Particularly, the second metal layer 60 and the first metal layer 40 mayhave the same or different materials.

A step S4, as shown in FIG. 6, the first preliminary pattern 31 and thesecond preliminary pattern 32 is irradiated with UV light from above thebase substrate 10 by using the gate 61 as a shielding layer, such that aportion of the first preliminary pattern 31 correspondingly located attwo side of the gate 61 and respectively connected to the connectingblock 41 and the second preliminary pattern 32 is conductorized under UVlight irradiation to form a source 71 and a drain 72 spaced apart, thesecond preliminary pattern 32 is conductorized under UV lightirradiation to form a pixel electrode 75, and a portion of the firstpreliminary pattern 31 located between the source 71 and the drain 72and shielded by the gate 61 forms a semiconductor channel 73.

Particularly, the pixel electrode 75 has a slit structure including aplurality of strip-shaped branch electrodes spaced apart, and the slitsare formed between adjacent strip-shaped branch electrodes.

It should be noted that, since the organic photoresist bump 20 has acertain thickness and the material thereof is a light-shieldingmaterial, the semiconductor channel 73 affected by the backlight thatdamages the semiconductor properties thereof can be avoided by theorganic photoresist bump 20 when the TFT substrate is applied to thedisplay panel. Moreover, the convex organic photoresist bump 20 isbeneficial to reduce the area occupied by the TFT device on the basesubstrate 10, thereby increasing an aperture ratio of the TFT substrate.

In the manufacturing method of the TFT substrate of the presentinvention, the metal oxide semiconductor layer 30 is irradiated with UVlight by using the gate as the shielding layer, such that the portion ofthe metal oxide semiconductor layer 30 irradiated by the UV light isconductorized to form the source 71, the drain 72, and the pixelelectrode 75, and the portion of the metal oxide semiconductor layer 30shielded by the gate 61 still retains the semiconductor properties toform the semiconductor channel 73. The invention achieves the alignmentof the source and drain 71/72 with the gate 61 by the processes ofself-alignment of the gate and the conductorization of the metal oxidesemiconductor layer, and the overlapping region of the source and drain71/72 and the gate 61 can be effectively controlled. Thereby, theparasitic capacitance is reduced, and the display quality is improved.Also, the manufacturing method is simple, and the production efficiencyis improved.

Referring to FIG. 6, based on the manufacturing method of the TFTsubstrate, the present invention further provides a TFT substrate whichis fabricated by the aforementioned manufacturing method of the TFTsubstrate, and the TFT substrate particularly includes the basesubstrate 10 and the metal oxide semiconductor layer 30, the first metallayer 40, the gate insulating layer 50, and the second metal layer 60sequentially deposited on the base substrate 10 from bottom to top.

Particularly, the metal oxide semiconductor layer 30 includes thesemiconductor channel 73 and the source 71, the drain 72, and the pixelelectrode 75 which are conductorized.

Particularly, the first metal layer 40 includes the data line 45 and theconnecting block 41 respectively connected to the data line 45 and thesource 71 on both ends, wherein the portion of the source 71 in contactwith the connecting block 41 is induced to be conductorized by theheated high temperature connecting block 41.

Particularly, the second metal layer 60 includes the gatecorrespondingly covering the semiconductor channel 73 and the gate line65 vertically insulated and crossed with the data line 45 and connectedto the gate 61.

Particularly, the source 71, the drain 72, and the pixel electrode 75which are not covered by the gate 61 and the connecting block 41 areconductorized by the UV light irradiation. The pixel electrode 75 isconnected to the drain 72. The source 71 and the drain 72 arerespectively connected to the semiconductor channel 73 from both sidesof the semiconductor channel 73 and are spaced apart by thesemiconductor channel 73. The opposite inner side edges of the source 71and the drain 72 are aligned with two side edges of the gate 61.

Particularly, The TFT substrate further includes the organic photoresistbump 20 disposed between the base substrate 10 and the metal oxidesemiconductor layer 30. The source 71, the semiconductor channel 73, andthe drain 72 connected together correspondingly cover the organicphotoresist bump 20.

Further, the material of the organic photoresist bump 20 is alight-shielding material, and the height of the organic photoresist bump20 is greater than 2 μm. Since the organic photoresist bump 20 has thecertain thickness and the material thereof is the light-shieldingmaterial, the semiconductor channel 73 affected by the backlight thatdamages the semiconductor properties can be avoided by the organicphotoresist bump 20 when the TFT substrate is applied to the displaypanel. Moreover, the convex organic photoresist bump 20 is beneficial toreduce the area occupied by the TFT device on the base substrate 10,thereby increasing the aperture ratio of the TFT substrate.

Particularly, the material of the metal oxide semiconductor layer 30 maybe indium gallium zinc oxide (IGZO), indium zinc tin oxide (IZTO), orindium gallium zinc tin oxide (IGZTO). In the present embodiment, themetal oxide semiconductor layer 30 is preferably IGZO.

Particularly, the portion of the first metal layer 40 in contact withthe metal oxide semiconductor layer 30 is a metal inducing layer whichcan induce the metal oxide semiconductor layer 30 to be conductorized athigh temperature, and the material of the metal inducing layer isaluminum, nickel, etc. In the present embodiment, the first metal layer40 is preferably a molybdenum aluminum stacked layer (Mo/AI), whereinthe aluminum layer is in contact with the metal oxide semiconductorlayer 30.

Particularly, the gate insulating layer 50 is a silicon oxide layer, asilicon nitride layer, or a combination thereof.

Particularly, the second metal layer 60 and the first metal layer 40 mayhave the same or different materials.

Particularly, the pixel electrode 75 has a slit structure including aplurality of strip-shaped branch electrodes spaced apart, and the slitsare formed between adjacent strip-shaped branch electrodes.

The TFT substrate of the present invention is fabricated by theaforementioned manufacturing method of the TFT substrate, which achievesthe alignment of the source and drain 71/72 with the gate 61 by theprocesses of self-alignment of the gate and the conductorization of themetal oxide semiconductor layer, and the overlapping region of thesource and drain 71/72 and the gate 61 can be effectively controlled.Thereby, the parasitic capacitance is reduced, and the display qualityis improved. Also, the manufacturing method is simple, and theproduction efficiency is improved.

In summary, in the manufacturing method of the TFT substrate provided bythe present invention, the metal oxide semiconductor layer is irradiatedwith UV light by using the gate as the shielding layer, such that theportion of the metal oxide semiconductor layer irradiated by the UVlight is conductorized to form the source, the drain, and the pixelelectrode, and the portion of the metal oxide semiconductor layershielded by the gate still retains semiconductor properties to form thesemiconductor channel. The invention achieves the alignment of thesource and drain with the gate by the processes of self-alignment of thegate and the conductorization of the metal oxide semiconductor layer,and can effectively control the overlapping region of the source anddrain and the gate. Thereby, the parasitic capacitance in the device isreduced, the RC loading when transmitting the signal is reduced, and thedisplay quality is improved. Also, the manufacturing method is simple,and the production efficiency is improved. The TFT substrate isfabricated by the aforementioned manufacturing method of the TFTsubstrate, and can effectively control the overlapping region of thesource and drain and the gate. Thereby, the parasitic capacitance in thedevice is reduced, the RC loading when transmitting the signal isreduced, and the display quality is improved.

Based on the description given above, those having ordinary skills ofthe art may easily contemplate various changes and modifications of thetechnical solution and technical ideas of the present invention and allthese changes and modifications are considered within the protectionscope of right for the present invention as defined in the appendedclaims.

1. A manufacturing method of a TFT substrate, comprising: a step S1 ofproviding a base substrate, depositing a metal oxide semiconductor layeron the base substrate, and patterning the metal oxide semiconductorlayer to obtain a first preliminary pattern and a second preliminarypattern connected to a side of the first preliminary pattern; a step S2of depositing a first metal layer on the base substrate and the metaloxide semiconductor layer, and patterning the first metal layer toobtain a connecting block connected to another side of the firstpreliminary pattern, heating the connecting block, thereby inducing aportion of the first preliminary pattern in contact with the connectingblock to be conductorized; a step S3 of depositing a gate insulatinglayer on the base substrate, the metal oxide semiconductor layer, andthe first metal layer, depositing a second metal layer on the gateinsulating layer, and patterning the second metal layer to obtain a gateacross the first preliminary pattern; a step S4 of irradiating the firstpreliminary pattern and the second preliminary pattern with UV lightfrom above the base substrate by using the gate as a shielding layer,such that a portion of the first preliminary pattern correspondinglylocated at two side of the gate and respectively connected to theconnecting block and the second preliminary pattern is conductorizedunder UV light irradiation to form a source and a drain spaced apart,the second preliminary pattern is conductorized under the UV lightirradiation to form a pixel electrode, and a portion of the firstpreliminary pattern located between the source and the drain andshielded by the gate forms a semiconductor channel.
 2. The manufacturingmethod of the TFT substrate according to claim 1, wherein the step S1further comprises forming an organic photoresist bump on the basesubstrate before depositing the metal oxide semiconductor layer, and thefirst preliminary pattern correspondingly covers the organic photoresistbump on the base substrate.
 3. The manufacturing method of the TFTsubstrate according to claim 2, wherein a material of the organicphotoresist bump is a light-shielding material; and a height of theorganic photoresist bump is greater than 2 μm.
 4. The manufacturingmethod of the TFT substrate according to claim 1, wherein a portion ofthe first metal layer in contact with the metal oxide semiconductorlayer is a metal inducing layer, and a material of the metal inducinglayer is aluminum.
 5. The manufacturing method of the TFT substrateaccording to claim 1, wherein the first metal layer after patterning inthe step S2 further comprises a data line connected to the connectingblock.
 6. A TFT substrate, comprising a base substrate and a metal oxidesemiconductor layer, a first metal layer, a gate insulating layer, and asecond metal layer sequentially deposited on the base substrate frombottom to top; the metal oxide semiconductor layer comprising asemiconductor channel and a source, a drain, and a pixel electrode whichare conductorized; the first metal layer comprising a connecting blockconnected to the source; the second metal layer comprising a gatecorrespondingly covering the semiconductor channel; the pixel electrodebeing connected to the drain, the source and the drain beingrespectively connected to the semiconductor channel from both sides ofthe semiconductor channel and being spaced apart by the semiconductorchannel, opposite inner side edges of the source and the drain arealigned with two side edges of the gate.
 7. The TFT substrate accordingto claim 6, further comprising an organic photoresist bump disposedbetween the base substrate and the metal oxide semiconductor layer; thesource, the semiconductor channel, and the drain connected togethercorrespondingly covering the organic photoresist bump.
 8. The TFTsubstrate according to claim 7, wherein a material of the organicphotoresist bump is a light-shielding material; and a height of theorganic photoresist bump is greater than 2 μm.
 9. The TFT substrateaccording to claim 6, wherein a portion of the first metal layer incontact with the metal oxide semiconductor layer is a metal inducinglayer, and a material of the metal inducing layer is aluminum.
 10. TheTFT substrate according to claim 6, wherein the first metal layerfurther comprises a data line connected to the connecting block; and thesecond metal layer further comprises a gate line vertically insulatedand crossed with the data line and connected to the gate.